Electronic devices such as laptops, desktops, mobile phones and other devices may employ one or more graphics processing circuits such as a graphics processor (e.g. a graphics core co-located on a dye with a host CPU, separate chip coupled to a mother board, or located on a plug-in card, a graphics core integrated with a memory bridge circuit, or any other suitable configuration) to provide graphics data and/or video information, video display data to one or more displays.
One type of communication interface design to provide the necessary high data rates and communication performance for graphics and/or video information between a graphics processor and CPU or any other devices is known as a PCI Express™ interface. This is a communication link that is a serial communications channel made up of sets of two differential wire pairs that provide for example 2.5 MBytes per second (Gen 1) or 5.0 MBytes per second (Gen 2) in each direction. Up to 32 of these “lanes” may be combined in times 2, times 4, times 8, times 16, times 32 configurations, creating a parallel interface of independently controlled serial links. However, any other suitable communication link may also be employed. Due to the ever increasing requirements of multimedia applications that require the generation of graphics information from drawing commands, or a suitable generation of video puts increasing demands on the graphics processing circuitry and system. This can require larger integrated graphics processing circuits which generate additional heat requiring cooling systems such as active cooling systems such as fans and associated ducting, or passive cooling systems in desktops, laptops or other devices. There are limits to the amount of heat that can be dissipated by a given electronic device.
It has been proposed to provide external graphics processing in a separate device from the laptop, desktop or mobile device to allow faster generation of graphics processing through parallel graphics processing operations or to provide output to multiple displays using external graphics devices. However, since devices are becoming smaller and smaller there is an ever increasing need to design connections, including connectors and cabling that allow proper consumer acceptance and suitable speed and cost advantages. Certain video games for example may require high bandwidth graphics processing which may not be available given the cost, integrated circuit size, heat dissipation, and other factors available on a mobile device or non-mobile device.
From an electrical connector standpoint, for years there have been attempts by various industries to design connectors that provide the requisite bandwidths such as the multiple gigabytes necessary to communicate video frame information and/or graphics information between devices. One proposal has been to provide an external cable and circuit board connector that uses for example a 16 lane configuration for PCI-e™. This proposal results in a printed circuit board footprint of approximately 40.3 mm×26.4 mm and a connector housing depth profile 40.3 mm×11.9 mm which includes the shell depth and housing of the connector. However, such large connectors have only been suitable for larger devices such as servers which can take up large spaces and can be many pounds in weight. For the consumer market such large connectors are too large and costly. A long felt need has existed for a suitable connector to accommodate multiple lanes of communication to provide the necessary bandwidth for graphics and video information.
Other connectors such as Display Port™ connectors are limited to only for example two lanes, although they have smaller footprints they cannot support the PCI-e™ express cable specification features and have limited capabilities. Other proposals that allow for, for example a 16 lane PCI-e™ connection have even larger footprints and profiles and may employ for example 138 pin total stacked connector to accommodate 16 lanes (VHDCI). The size of the footprint and profile can be for example in excess of 42 millimeters by 19 millimeters for the footprint and in excess of 42 by 12 millimeters in terms of the PCI-e™ board profile that the connector takes up. Again, such connectors require the size of the mobile device or laptop device to be too large or can take up an unreasonable amount of real estate on the PC board or device housing to accommodate the size of such large connectors. In addition, such connectors also utilize large cabling which can be heavy and cumbersome in use with laptop devices. The costs can also be unreasonably high. In addition, motherboard space is at a premium and as such larger connectors are not practical.
From an electronic device perspective, providing external graphics processing capability in a separate device is also known. For example, docking stations are known that employ a PCI-e™ express interface connector that includes a single lane to communicate with the CPU in for example a laptop computer that is plugged into the docking station. The docking station includes its own A/C connector and has additional display connector ports to allow external displays to be connected directly to the docking station. The laptop which may have for example its own LCD display and internal graphics processing circuitry in the form of an integrated video/graphics processing core or card, utilizes the laptop's CPU to send drawing commands or compressed video via the single lane PCI-e™ express connector to the external graphics processor located in the docking station. However, such configurations can be too slow and typically employ a low end graphics processor since there is only a single lane of communication capability provided.
Other external electronic units that employ graphics processing circuitry to enhance the graphics processing capabilities of a desktop, laptop or other device are also known that employ for example a signal repeater that increases the signal strength of graphics communications across a multilane PCI-e™ connector. However, the connector is a large pin connector with large space in between pins resulting in a connector having approximately 140 pins if 16 lanes are used. The layout requirements on the mother board as well as the size of the connectors are too large. As a result, actual devices typically employ for example a single lane (approximately 18 pin connector) connector including many control pins. As such, although manufacturers may describe wanting to accommodate multilane PCI-e™ express communications, practical applications by the manufacturers typically result in a single lane configuration. This failure to be able to suitably design and manufacture a suitably sized connector has been a long standing problem.
Other external devices allow PCI-e™ graphics cards to be used in notebooks. Again these typically use a single lane PCI-e™ express connector. Such devices may include a display panel that displays information such as a games current frame rate per second, clock speed and cooling fan speed which may be adjusted by for example a function knob or through software as desired. A grill may be provided for example on a rear or side panel so that the graphics card may be visible inside and may also provide ventilation. The internal graphics card may be over-clocked in real time by turning a control knob for example to attempt to increase performance of the external graphics processing capability. However, as noted, the communication link between the CPU and the laptop and the external electronic device with the graphics card typically has a single PCI-e™ express lane limiting the capability of the graphics card.
Also, systems that use multiple graphics processors such as graphics processor cores that are included as part of a Northbridge circuit, CPU, or any other circuit and can generate or render frames based on drawings commands and/or video processing commands. As known in the art drawing commands may be, for example, 3D drawing commands and video processing commands may be commands to decode compressed video or otherwise process video as known in the art. Such systems can generate undesirable amounts of thermal output and consume undesirable amounts of power. A known system attempts to utilize multiple graphics processors to speed up processing to improve performance for a user. For example, a graphics processor (e.g., core with one or more pipelines) is used to provide and generate one frame for display while another graphics processor is used to generate another frame. Multiplexing circuitry is then used to output a rendered frame from a respective frame buffer corresponding to each of the differing graphics processors. However, such rendering is typically done in parallel. In another system, a host graphics processor and its corresponding frame buffer receives a copy of a frame that has been rendered by another graphics processor and stores the copied frame in its local frame buffer. However while the host GPU is using its display engine to display the frame from its local frame buffer that was copied into it by the other graphics processor, it is also using its rendering engine to render portions of another frame in parallel with the remote graphics processor. As such, such systems attempt to provide rendering in parallel thereby increasing the processing capability of the system but also increasing the power usage and thermal output generated.
Also, there is a need to reduce heat produced and power consumed by graphics processors (e.g., cores) in devices such as laptops, handheld devices, desktops and other devices with one or more graphics processors therein.